na-adjective, noun
simple and honest; unsophisticated sincerity
Describes a person or character that is straightforward, unpretentious, and sincere, sometimes with a nuance of artless naivety. Often used positively for rustic honesty.
彼の朴直な人柄に心を打たれた。
I was touched by his simple and honest personality.
朴直な青年が都会で苦労する話だ。
It's a story about a naive young man struggling in the city.
素朴 means 'simple and unsophisticated' in a broader sense, often applied to things or questions, while 朴直 specifically emphasizes honesty and straightforwardness of character.
純朴 also means 'simple and honest,' but carries a stronger nuance of purity and innocence, often associated with rural or childlike simplicity.
Compound of 朴 (simple, plain) and 直 (straight, honest). The exact historical derivation is uncertain, but the combination conveys straightforward simplicity.